My dog knows how to speak but is just physical incapable of speaking
She's (Dachshund-Chihuahua, F13) always trying to speak but shes only capable of whimpering and screaming really loudly. She's very clearly trying to move how mouth the way we move our lips, but she simply cannot move her dog lips and toung with as much precision as human lips. I can tell it pains her so that she still can't get through to us.